The U.S. Supreme Court has ruled that states may restrict participation in girls' and women's school sports based on biological sex, handing a major victory to states that have enacted bans on transgender athletes and to supporters who argue the policies protect competitive fairness.

In a 6-3 decision split along ideological lines, the court upheld laws in Idaho and West Virginia that prohibit biological males from competing on girls' and women's school sports teams. The ruling is expected to shape the future of similar laws already enacted in more than half of U.S. states and could significantly influence how schools nationwide interpret Title IX and the Constitution.

Majority Says States Can Base Eligibility on Biological Sex

Writing for the majority, Justice Brett Kavanaugh concluded that neither the Constitution nor Title IX prevents states from limiting girls' and women's sports to biological females.

"In other words, may schools determine eligibility for women's and girls' sports based on biological sex? The answer is yes."

Kavanaugh wrote that states are permitted to preserve female-only athletic competition under both Title IX and the Equal Protection Clause.

"Consistent with Title IX and the Equal Protection Clause, we hold that the States may maintain women's and girls' sports for biological females. They may determine eligibility for women's and girls' sports based on biological sex. The Constitution and Title IX do not require an overhaul of women's and girls' sports throughout America."

The decision overturns lower court rulings that had blocked Idaho's law and allows both Idaho and West Virginia to enforce their restrictions.

Liberal Justices Warn Court Acted Too Broadly

The court's three liberal justices dissented, arguing the majority reached sweeping conclusions without fully examining the facts underlying the cases.

Justice Sonia Sotomayor, joined by Justices Elena Kagan and Ketanji Brown Jackson, criticized the court's reasoning.

"Its holding may be straightforward, but that is not the point."

She argued the majority departed from existing legal precedent and resolved a highly divisive issue without sufficient factual development.

"The problem is how the majority gets there: by moving the goalposts set by precedent and by resolving this important, divisive issue without knowing all the facts even though the validity of the means-ends fit depends on them."

Cases Centered on Idaho and West Virginia Laws

The ruling stems from challenges to laws enacted in Idaho and West Virginia after Republican-led states began adopting restrictions on transgender participation in school athletics.

Idaho became the first state to pass such a law in 2020. West Virginia soon followed as similar legislation spread across the country.

The Idaho case was brought by Lindsay Hecox, a biological male who sought to compete on Boise State University's women's track and cross-country teams. After Idaho appealed adverse lower court rulings, Hecox informed the Supreme Court there were no longer plans to compete and urged the justices to dismiss the case.

The West Virginia challenge involved Becky Pepper-Jackson, a high school athlete who has publicly identified as female since the third grade. Pepper-Jackson, a shot put and discus competitor, became the only known athlete directly affected by the state's ban and recently won the West Virginia AAA girls' state championship in shot put while litigation remained ongoing.

The athletes argued that the laws violated the Equal Protection Clause of the 14th Amendment and Title IX, the federal law prohibiting sex discrimination in education.

Decision Carries National Implications

The Supreme Court's ruling is expected to have consequences well beyond Idaho and West Virginia.

More than half the states have enacted laws restricting transgender athletes from competing in girls' and women's sports, primarily in Republican-controlled legislatures. Tuesday's decision provides those states with the strongest legal backing yet for maintaining those policies.

The cases also drew widespread national attention, with advocacy groups, state governments and athletic organizations weighing in.

LGBTQ advocacy organizations, the American Civil Liberties Union, the National Women's Law Center and 15 Democratic-led states supported the athletes challenging the bans.

Backing the states were the Trump administration, approximately two dozen Republican-led states, the U.S. Conference of Catholic Bishops, The Church of Jesus Christ of Latter-day Saints and several athletes who have publicly advocated for restrictions on transgender participation in women's sports, including former collegiate swimmer Riley Gaines.

Part of a Broader National Debate

The ruling arrives as transgender participation in sports remains one of the country's most debated social and political issues.

Supporters of the bans argue they preserve competitive fairness and protect opportunities created for female athletes under Title IX. Opponents contend the restrictions discriminate against transgender students and exclude them from school athletics.

The Supreme Court's decision comes amid broader efforts by President Donald Trump during his second term to roll back federal protections for transgender individuals.

On his first day back in office, Trump signed an executive order declaring that the federal government recognizes only two immutable sexes—male and female. The order also prohibited federal agencies from promoting what it described as "gender ideology" and directed the administration to withhold certain federal funding from programs allowing transgender girls to compete on teams consistent with their gender identity.

The administration has also pursued policies restricting transgender military service and limiting access to gender-affirming medical care for minors.

What Happens Next?

The Supreme Court's decision establishes that states may determine eligibility for girls' and women's school sports based on biological sex without violating Title IX or the Equal Protection Clause.

While legal challenges over transgender rights are likely to continue in other areas—including healthcare, education and public accommodations—the ruling represents one of the court's most significant decisions on transgender issues to date and provides a constitutional framework that will guide future disputes over school athletics across the country.